Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial

Lead Contacts and/or Principal Investigators (PIs):

  • Neal Freedman, Ph.D., M.P.H.
    Division of Cancer Epidemiology and Genetics (DCEG), National Cancer Institute (NCI)
  • Paul Pinksy, Ph.D.
    Division of Cancer Prevention (DCP), NCI

Funded Since: 1992
Funding Source: NCI Extramural Program (DCP) and NCI Intramural Program (DCEG). DCP provided funding for the trial and biospecimen collection, and DCEG provided funding for biospecimen storage.
Year(s) of Enrollment: 1993-2001
Study Website:

The Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial is a large-scale clinical trial to determine whether certain cancer screening tests reduce deaths from prostate, lung, colorectal, and ovarian cancer. The underlying rationale for the trial is that screening for cancer may enable doctors to discover and treat the disease earlier. Numerous epidemiologic and ancillary studies are included to answer related crucial questions.

Together, these four cancers are estimated to account for about 40 percent of all diagnosed cancers in the United States and 45 percent of cancer deaths in 2009.

Sponsored and run by NCI’s Division of Cancer Prevention (DCP), in collaboration with the Division of Cancer Epidemiology and Genetics (DCEG), the PLCO Trial is taking place at ten screening centers across the country.

Between 1992, when the trial opened, and by 2001, when enrollment ended, 155,000 women and men between the ages of 55 and 74 who had no previous diagnosis of cancer of the prostate, lung, colon/rectum, or ovary had joined. At entry, participants were randomly divided into one of two study groups. One group received routine health care from their health providers. The other group received a series of exams to screen for prostate, lung, colorectal, and ovarian cancers. Screening of participants ended in late 2006. Active follow-up is continuing for up to 14 years as originally scheduled, with an additional follow-up for at least five years being planned. New findings are noted as they are published on the  PLCO News Updates and Publications Web pages.

With more than 2.6 million biological samples collected, the PLCO Trial is a rich and unique resource for etiologic and early marker studies. The Etiology and Early Marker Studies (EEMS) is a critical component of the PLCO Trial. By collecting biologic materials and risk factor information from trial participants before the diagnosis of disease, the EEMS adds substantial value by providing a resource for ancillary research projects investigating cancer etiology and early markers for detection of cancer.

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